@fourk Interned the rollup name constant and placed it in RollupEventEmitter in 09db636. But we cannot change the method signature to 
```
emit(RollupEvent... rollupEvents) {
  super.emit(ROLLUP_EVENT_NAME, rollupEvents);
}
```
because we are overriding the method 
```
public Future emit(String event, T... args)
```
in base class of `Emitter`.